The anti-rheumatic activity of 2-(3-phenoxy-phenyl)-propionic acid (Fenoprofen) is known.
Several methods are disclosed for the preparation of the compound. The compound has been prepared for example by hydrolysis of 2-(phenoxy-phenyl)-3-propionitrile with sodium hydroxide in 50% aqueous ethanol for 72 hours (Swiss patent specification No. 527 155). The starting nitrile was prepared by methylation of m-phenoxy-acetophenone followed by reduction to .alpha.-methyl-3-phenoxy-benzyl alcohol with sodium borohydride and followed by halogenation of the obtained product to .alpha.-methyl-3-phenoxy-benzyl bromide with phosphorus tribromide and reaction with sodium cyanide in anhydrous dimethyl sulfoxide (Swiss patent specification No. 527 155). According to another process .alpha.-methyl-.alpha.-(3-phenoxy-phenyl)-malonic acid is decarboxylated in a melt at 130.degree.-160.degree. C. The starting material was prepared by reacting .alpha.-(3-phenoxy-phenyl)-acetic acid diethyl ester with diethyl carbonate to obtain .alpha.-methyl-.alpha.-(3-phenoxyphenyl)-malonic acid diethyl ester which was hydrolyzed in aqueous alcohol by boiling it together with sodium hydroxide. The reaction mixture of the last step was purified by washing with ether in order to remove the starting ester as the hydrolysis was only partial (Swiss patent specification No. 527 155).
Further processes comprise reacting phenoxy-phenylmagnesium bromide with the sodium salt of 2-bromo propionic acid in ether medium (Hungarian patent specification No. 168 376); reacting 1-propynyl-3-(phenoxy)-benzene with thallium nitrate in the presence of alcohol (Hungarian patent specification No. 173 576); oxidizing 1-isobutenyl-3-phenoxy-benzene (Spanish patent specification No. 464 352); and oxidizing phenoxy-phenylpropionic acid aldehyde with silver oxide (German Patent Publication No. 2 533 397).